Gas turbine comprising thermal energy store, method for operating same, and method for modifying same

ABSTRACT

An energy generation plant in which the exhaust gas from a gas turbine is guided into a thermal energy store, wherein the thermal energy store can be used for various purposes. The energy generation plant has at least one gas turbine having an exhaust gas apparatus, at least one generator, at least one thermal energy store, wherein the generator can be driven by the gas turbine, wherein the hot exhaust gas from the gas turbine is passed directly to a thermal energy store via the exhaust gas apparatus, wherein the thermal energy from the thermal energy store can be used to generate power.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the US National Stage of International ApplicationNo. PCT/EP2020/059430 filed 2 Apr. 2020, and claims the benefit thereof.The International Application claims the benefit of German ApplicationNo. DE 10 2019 210 737.0 filed 19 Jul. 2019. All of the applications areincorporated by reference herein in their entirety.

FIELD OF INVENTION

The invention relates to a plant in which the exhaust gas from a gasturbine is guided into a thermal energy store, wherein the thermalenergy store can be used for various purposes.

BACKGROUND OF INVENTION

In the current energy market, gas turbines are often used as so-called“peakers” and must therefore be started up and shut down quickly interms of their power. This is not possible from the quiescent state andallowing the gas turbine to continue to run does not appear to be usefuleither.

SUMMARY OF INVENTION

Therefore, the object of the invention is to solve the problem mentionedabove.

The object is achieved by means of a plant, a method for operating aplant, and a modifying method as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a combined-cycle plant according to the prior art.

FIGS. 2, 3 and 4 schematically illustrate the invention.

DETAILED DESCRIPTION OF INVENTION

The drawing and the description represent only exemplary embodiments ofthe invention.

FIG. 1 shows, by way of example, an energy conversion plant 1′. A gasturbine 100 is coupled to a generator 5 for generating power via atransmission 4 or a coupling 4.

The generator 5 is likewise connected to a steam turbine 6 via acoupling 2.

Steam turbines 6 are present when it is a combined-cycle power plant. Anenergy conversion plant 1 may also only have a gas turbine 100 without asteam turbine 6.

A condenser 7 is connected to the steam turbine 6, if present.

The exhaust gas from the gas turbine 100 flows, via an exhaust gasapparatus or via a diffuser 8, into a heat recovery plant (HRSG) 9 inwhich the hot exhaust air is used to generate steam. An exhaust airchimney 10 is likewise present.

FIG. 2 schematically illustrates a plant 1 according to the invention.

The hot exhaust gas from the gas turbine 100 is guided into an energystore 103 via the diffuser 8.

If necessary, the energy from the energy store 103 can be taken in orderto heat water for district heating and to feed it into the districtheating system or, like in this example here, it is used to generatesteam for a combined-cycle plant. Optionally, power from renewableenergy from wind power plants 106 or solar energy plants 109 can also besupplied to the thermal energy store 103, in particular by means of anelectrical heater 36.

Depending on the application, in particular in the case of thecombined-cycle plant, there is a bypass 112 which either guides the hotexhaust gas from the gas turbine 100 directly into the thermal energystore 103 or into the heat recovery system (HRSG) 9.

In the present case, chimneys 25, 26, 27 are also provided, wherein thechimney 25 is assigned to the heat recovery system 9, the chimney 26 isassigned to the energy store 103 and the chimney 27 is assigned to thebypass 112.

If the gas turbine 100 is operated at full load and its energy is neededto drive the generator 5, all or most of the exhaust gas from the gasturbine is guided directly into the thermal energy store 103.

During combined-cycle operation, the hot exhaust gas from the gasturbine 100 can be guided into the HRSG 9 and/or into the thermal energystore 103, depending on the network utilization.

If less electricity is needed in the network, the gas turbine 100 can beshut down to a particular extent. In this case, the thermal energy store103 need not be loaded any further.

If necessary, the thermal energy store 103 is discharged in order tooperate the steam turbine 6 which then in turn drives the generator 5 orkeeps the boiler warm.

If the gas turbine is operated as a “peaker” or is operated in the opencycle, wherein this may be a single gas turbine or a gas turbine in acombined-cycle plant 1, the hot exhaust gas from the gas turbine 100 ismainly or completely used to load the thermal energy store 103.

As means 9, a steam turbine 6 and upstream processes can be used, asshown in FIG. 3, to use the stored energy in the energy store 103 togenerate electricity.

FIG. 3 shows a detailed arrangement of the plant 1 according to theinvention.

The gas turbine 100 which is operated in the open cycle or simple cycleor combined-cycle operation is shown in the upper region. The hotexhaust gas from the gas turbine 100 can be supplied to the thermalenergy store 103 via the line 13′. The energy store 103 advantageouslyhas, as storage material, temperature-stable stones with a high heatdensity or ceramic materials. The storage material defines amultiplicity of gas channels through which the hot exhaust gas can flow.The storage medium is provided, on the outside, with an insulation whichcan be produced, for example, from fire bricks or the like. Theinsulation should be designed such that the temperature on the outsidedoes not exceed 60°. The exhaust gas temperature and the exhaust gasmass flow while loading the energy store 103 depend on the type of gasturbine used. In the case of Siemens gas turbine of the type 2000E, theexhaust gas temperature is approximately 550° C., for example, and theexhaust gas mass flow is approximately 560 kg/s and, in the case of aSiemens gas turbine of the type 4000 F, the exhaust gas temperature isapproximately 605° C. and the exhaust gas mass flow is 650 kg/s. Thestorage medium of the energy store 103 and its gas channels should beconfigured in such a manner that, during loading, a maximum permissiblecounterpressure, which could jeopardize the proper method of operationof the gas turbine 100, is not exceeded. The energy may likewise betaken from the thermal energy store 103 in the form of hot air in orderto guide it to a means 6, 9, 30 for the purpose of generating power. Forthis purpose, the hot air is guided from the energy store 103 via adischarge line 13″ in order to generate hot steam for a steam turbine 6,which drives a generator 5, in the present case by means of a condenser16, a pump 19 and a heat recovery plant 9 (heat exchanger). In thepresent case, a fan 14 is used to guide the hot air from the energystore 103 or to discharge the energy store 103, which fan is connectedto one side of the energy store 103 via a supply line 17 and isconnected to another side of the energy store 103, to which thedischarge line 13″ is also connected, via a bypass line 18. If cold airis applied to the energy store 103 using the fan 14 via the supply line17, the hot air stored in the energy store 103 emerges on the other sideof the energy store 103 and the discharge line 13″ is initiated. Inorder to reduce the temperature of the hot air leaving the energy store103, it can be mixed, if necessary, with an adjustable or controllablemass flow of cold air which is supplied via the bypass line 18. In thepresent case, the fan 14 is designed such that it generates a mass flowof approximately 350 kg/s.

It is likewise possible to use the energy from the thermal energy store103 to heat water when using refrigeration machines, expansion machines,process heat for drying plants or for district heating by coupling outthe energy via one of the chimneys 25, 26, 27.

FIG. 4 shows a further variant in which, in supplementation of FIG. 3,renewable energies such as wind energy, solar energy or electricity fromreservoirs 23 are used to heat the thermal energy store 103 by means ofan electrical heater 36, optionally to heat exhaust gas.

The part of the gas turbine 100 or combined-cycle plant 1 is onlyschematically illustrated in FIG. 3 and FIG. 4 and corresponds to FIG. 1or 2.

The thermal energy store 103 advantageously has a modular structure.Individual modules can be heated separately from one another and cantherefore be brought to different temperatures.

High temperatures in the energy store 103 are thermodynamically best.

If a module reaches the highest temperature, another module can beheated.

Accordingly, the module with the highest temperature is “discharged”first in order to use it for the steam turbine 6 or HRSG 9, inparticular.

1. An energy generation plant, comprising: at least one gas turbinehaving an exhaust gas apparatus, at least one generator, at least onethermal energy store, wherein the generator is adapted to be driven bythe gas turbine, wherein hot exhaust gas from the gas turbine preferablyis adapted to be passed directly to a thermal energy store via theexhaust gas apparatus, and means for using the thermal energy from thethermal energy store at least partially, in particular only, to generatepower.
 2. The plant as claimed in claim 1, wherein the plant does notuse any power from renewable energies, from wind, from hydro energy,from solar energy, to heat the thermal energy store.
 3. The plant asclaimed in claim 1, wherein the plant is adapted to use power from windand/or hydro energy and/or solar energy to heat the thermal energystore, in particular by means of an electrical heater.
 4. The plant asclaimed in claim 1, wherein the plant does not use solar energy to heatair or other working fluids.
 5. The plant as claimed in claim 1, whereinthe plant is adapted to use superfluous power from an external powersupply system to heat the thermal energy store, in particular by meansof an electrical heater.
 6. The plant as claimed in claim 1, furthercomprising: in addition to the gas turbine, a steam turbine which isadapted to also drive a or the generator, wherein the thermal energystore is adapted to be used to operate the steam turbine.
 7. The plantas claimed in claim 1, further comprising: a heat recovery system, intowhich hot exhaust gas from the gas turbine or steam from a steam turbinecan pass.
 8. The plant as claimed in claim 1, further comprising: atleast one bypass between the exhaust gas apparatus of the gas turbineand the thermal energy store, which bypass makes it possible toselectively guide the hot exhaust gas from the gas turbine into thethermal energy store and/or into a heat recovery system.
 9. The plant asclaimed in claim 1, wherein the thermal energy store has a modularstructure in order to heat the energy store differently in individualmodules.
 10. The plant as claimed in claim 1, wherein the thermal energystore is discharged via a fan which supplies cold air to the energystore via a supply line in such a manner that hot air is pushed from theenergy store, wherein the hot air leaving the energy store canpreferably be mixed with a controllable mass flow of cold air which issupplied via a bypass line.
 11. The plant as claimed in claim 1, whichhas a single generator for a gas turbine and a steam turbine, inparticular in the form of a single-shaft plant.
 12. The plant as claimedin claim 1, wherein solar energy is not used to heat air or compressedair, neither for HRSG, the gas turbine nor the thermal energy store. 13.A method for operating an energy generation plant, at least having atleast one gas turbine having an exhaust gas apparatus, and at least onegenerator, at least one thermal energy store, the method comprising:driving the generator by the gas turbine, guiding the hot exhaust gasfrom the gas turbine via the exhaust gas apparatus, in particulardirectly, into the thermal energy store, in particular using only theexhaust gas from a gas turbine to heat the thermal energy store, andusing the thermal energy from the thermal energy store at least togenerate power.
 14. The method as claimed in claim 13, wherein the plantis a combined-cycle plant with a steam turbine and a thermal energystore, wherein the stored energy from the thermal energy store is usedto operate the steam turbine.
 15. The method as claimed in claim 13,wherein the hot exhaust gas from the gas turbine is selectivelyredirected into a thermal energy store or into a heat recovery system,in particular by means of a bypass.
 16. The method as claimed in claim13, wherein the energy store is selectively charged and discharged. 17.The method as claimed in claim 13, wherein the energy store isdischarged using a fan which pushes hot air from the energy store,wherein the hot air leaving the energy store can be mixed with acontrollable mass flow of cold air.
 18. The method as claimed in claim14, wherein electricity from solar, hydro and/or wind energy is used toadditionally heat up the thermal energy store, in particular by means ofan electrical heater, very particularly only electrical power fromsolar, hydro and/or wind energy is used.
 19. The method as claimed inclaim 14, wherein the gas turbine is operated in the open cycle.
 20. Themethod as claimed in claim 14, wherein the gas turbine is operated incombined-cycle operation.
 21. The method as claimed in claim 14, whereinonly the steam turbine in a combined-cycle plant is operated by means ofthe energy from the thermal energy store.
 22. The method as claimed inclaim 13, wherein solar energy is not used to heat air or compressedair, neither for the heat recovery system HRSG, the gas turbine, nor thethermal energy store.
 23. A method for modifying an existing energygeneration plant, in particular a combined-cycle plant, the methodcomprising: adding at least one thermal energy store, which can beheated by means of hot exhaust gas from a gas turbine.